1. Field of the Invention
The present invention relates to a self-propelled elevator in which a drive unit including an electric motor and a winding machine for winding up a cage of the elevator is arranged at the cage itself.
2. Description of Related Art
A rope type elevator requires a machine room, in which a winding machine and an electric motor are arranged, at the top of a hoistway. Therefore, the total height of a building in which the rope type elevator is installed is increased, and the construction cost of the building is raised, and further problems may be caused from the viewpoint of the right to sunshine.
In order to solve the above problems, there is proposed a self-propelled elevator in which a drive unit including a motor and a winding machine is arranged at a cage itself so that a machine room can be eliminated.
FIG. 10 is an arrangement view of a conventional self-propelled elevator disclosed in Japanese Unexamined Patent Publication No. 62-31686.
In the view, reference numeral 1 is a cage, reference numeral 2 is a guide rail, reference numeral 3 is a guide roller, reference numeral 4 is a drum type winding machine attached to the outside of the cage 1, reference numeral 5 is a winding rope, and reference numeral 6 is a hoistway. As shown in the view, according to the above conventional self-propelled elevator, the drum type winding machine 4 is arranged on the outside of the cage 1, and no machine room, which is necessary in the case of a rope type elevator, is provided at the top of the hoistway. Due to the above arrangement, it becomes possible to save a space in the direction of height of the hoistway. In this arrangement, the drum type winding machine 4 is arranged between the cage 1 and the hoistway 6.
However, the following problems may be encountered in the above conventional self-propelled elevator. In the above conventional self-propelled elevator, the drum type winding machine is arranged on the side of the cage between the outside of the cage and the wall of the hoistway. For the above reasons, although the space can be saved in the direction of the height of the hoistway, the plane space i.e. cross-sectional areas, of the hoistway is increased as compared with the conventional elevator in which the winding machine is arranged in the machine room.
Since the cage hanging position is located distant from the gravity center of the cage, an eccentric moment is generated in the cage. Therefore, loads given to the guide rails in the horizontal direction are increased.
Further, although not shown in FIG. 10, since the winding rope is wound round the winding drum sheave so that the winding rope can not overlap each other, a contact point of the winding rope with the winding drum sheave moves in the axial direction of the winding drum sheave.
Accordingly, a fleet angle, which is an angle by which the winding rope enters the rope groove of the winding drum sheave, fluctuates. Therefore, abrasion is caused in the winding rope and the suspension sheave.
Further, since the drum type winding machine is arranged at the cage, the weight of the cage is increased.
Accordingly, compared with the conventional arrangement in which the winding machine is arranged in the machine room, the size of the motor to drive the winding machine is increased, and further the electrical power consumption is increased.
The present invention has been accomplished to solve the above problems. It is an object of the present invention to reduce a plane space of a hoistway in a self-propelled elevator in which a cage is provided with a drum type winding machine.
It is another object of the present invention to reduce loads given to guide rails by preventing the generation of an eccentric moment caused by tension of a winding rope.
It is still another object of the present invention to reduce the fluctuation of a fleet angle of a winding rope so that the abrasion of a winding rope suspension sheave can be decreased and the reliability can be enhanced.
It is still another object of the present invention to reduce the size of an electric motor to drive a winding machine so that the electric power consumption can be reduced.
The present invention provides a self-propelled elevator in which a drum type winding machine is attached to a cage, and the cage is elevated along guide rails arranged in a hoistway by a first winding rope, one end of which is fixed to a top portion of the hoistway and the other end portion of which is directly wound round a winding drum sheave of the drum type winding machine, the self-propelled elevator characterized in that: the drum type winding machine is attached onto a lower side of a bottom portion of the cage so that an end face of the winding drum sheave round which the first winding rope is wound can be located outside a projected region of the cage in the perpendicular direction.
In a self-propelled elevator of the present invention, a suspension sheave is provided at a position opposed to the winding drum sheave on the lower side of the bottom of the cage, a second winding rope is provided, one end of which is fixed to a top of the hoistway and the other end of which is wound round the winding drum sheave after it has been wound round the suspension sheave, and the suspension sheave is arranged at a position so that an end face of the second winding rope which is wound round the suspension sheave from the top of the hoistway can be located outside the projected region of the cage in the perpendicular direction.
In a self-propelled elevator of the present invention, the suspension sheave is capable of swiveling.
In a self-propelled elevator of the present invention, the suspension sheave can be freely moved in a direction parallel with the axial direction of the winding drum sheave.
In a self-propelled elevator of the present invention, an outer circumferential portion of the suspension sheave round which the second winding rope is wound has a width of a predetermined length in a direction parallel with the axial direction of the winding drum sheave, and no grooves in which the second winding rope is wound are provided in the outer circumferential portion of the sheave.
In a self-propelled elevator of the present invention, a rope is provided, one end of which is fixed to the cage and the other end of which is fixed to a counterweight, and the rope is wound round a return sheave arranged at the top of the hoistway between the cage and the counterweight.
In a self-propelled elevator of the present invention, the weight of the counterweight is less than the self-weight of the cage.
In a self-propelled elevator of the present invention, the weight of the counterweight is not less than xc2xd of the self-weight of the cage and not more than xc2xd of the sum of the maximum carrying capacity and the self-weight of the cage.